#include<stdio.h>
#include<assert.h>
#include<string.h>
char sys2(char*s) {
    char*p=s,*q=s;
    while(*q)q++;
    q--;
    if(p<=q)
        return 1;
    while(p<q) {
        if(*p!=*q)
            return 0;
        p++,q--;
    }
    return 1;
}
int sys(char*p,char*q) { //[p,q]  bugs
    if(p<=q)
        return 1;
    return (*p)==(*q) && sys(p+1,q-1);
}


int main() {
    char s[100]="abbaaba";
    sys(s,s+strlen(s)-1);
}
